Equilibria chemical equilibria, dynamic equilibrium

chemical equilibria, dynamic equilibrium

1. iGCSE chemistry equilibria md kamrul alam khan

2. Content Physical Chemistry Equilibria

3. Equilibria Equilibria understand that some reactions are reversible and are indicated by the symbol ⇌ in equations describe reversible reactions such as the dehydration of hydrated copper(II) sulphate and the effect of heat on ammonium chloride understand the concept of dynamic equilibrium predict the effects of changing the pressure and temperature on the equilibrium position in reversible reactions.

4. k Reversible Reactions OK, let’s introduce you to a new symbol and concept.

5. Reversible Reactions X

6. Reversible Reactions

7. Reversible Reactions This is the symbol for a reversible reaction

8. Reversible Reactions A reversible reaction is one which can go in both directions.

9. Reversible Reactions This means that in a chemical reaction the products of the reaction can be turned back into the original reactants.

10. Reversible Reactions For example: A + B C + D

11. Reversible Reactions For example: A + B C + D A and B react to produce C and D, but also C and D can react to produce A and B.

12. Reversible Reactions Let’s look at an example

13. Reversible Reactions Heating blue copper sulphate Heat Water vapour

14. Reversible Reactions Heating blue copper sulphate Heat Water vapour White anhydrous copper sulphate

15. Reversible Reactions Blue hydrated copper sulphate White anhydrous copper sulphate Add a few drops of water

16. Reversible Reactions Blue hydrated copper sulphate White anhydrous copper sulphate Add a few drops of water CuSO 4 .5H 2 O CuSO 4 + 5H 2 O

17. Reversible Reactions Let’s look at another example – favourite one in the exams!

18. Reversible Reactions Let’s look at another example – favourite one in the exams! The Thermal Decomposition of ammonium chloride, NH 4 Cl

19. Reversible Reactions NH 4 Cl NH 3 + HCl Heat Water in and out Solid ammonium chloride Solid ammonium chloride Ammonia and HCl gases

20. Reversible Reactions NH 4 Cl NH 3 + HCl Heat Water in and out Solid ammonium chloride Solid ammonium chloride Ammonia and HCl gases 1. When heated. Ammonium chloride splits up into ammonia gas and hydrogen chloride gas.

21. Reversible Reactions NH 4 Cl NH 3 + HCl Heat Water in and out Solid ammonium chloride Solid ammonium chloride Ammonia and HCl gases When heated. Ammonium chloride splits up into ammonia gas and hydrogen chloride gas. As these gases cool on the bottom of the flask, they recombine to form solid ammonium chloride again.

22. Reversible Reactions NH 4 Cl NH 3 + HCl Heat Water in and out Solid ammonium chloride Solid ammonium chloride Ammonia and HCl gases When heated. Ammonium chloride splits up into ammonia gas and hydrogen chloride gas. As these gases cool on the bottom of the flask, they recombine to form solid ammonium chloride again. This is a good example of a reversible reaction because the products recombine to easily form the original reactants.

23. Reversible Reactions and Closed Systems

24. Reversible Reactions and Closed Systems Try to imagine a closed system where no more reactants are added, and no products are removed.

25. Reversible Reactions and Closed Systems

26. Reversible Reactions and Closed Systems A + B C + D A and B will be combining to form C and D, while at the same time C and D will be combining to form A + B.

27. Reversible Reactions and Closed Systems A + B C + D A point will eventually be reached when the rate of the forward reaction is equal to the rate of the backward reaction.

28. Reversible Reactions and Closed Systems A + B C + D This point is know as the DYNAMIC EQUILIBRIUM

29. Reversible Reactions and Closed Systems Temperature and equilibria A + B C + D If the forward reaction (i.e. going from left to right) is ENDOTHERMIC and heat energy is taken in ……..

30. Reversible Reactions and Closed Systems Temperature and equilibria A + B C + D If the forward reaction (i.e. going from left to right) is ENDOTHERMIC and heat energy is taken in …….. Then if the temperature is increased.

31. Reversible Reactions and Closed Systems Temperature and equilibria A + B C + D If the forward reaction (i.e. going from left to right) is ENDOTHERMIC and heat energy is taken in …….. Then if the temperature is increased. The yield of products is increased, and more heat is taken in.

32. Reversible Reactions and Closed Systems Temperature and equilibria A + B C + D If the forward reaction (i.e. going from left to right) is ENDOTHERMIC and heat energy is taken in …….. Then if the temperature is decreased

33. Reversible Reactions and Closed Systems Temperature and equilibria A + B C + D If the forward reaction (i.e. going from left to right) is ENDOTHERMIC and heat energy is taken in …….. Then if the temperature is decreased. The yield of products is decreased, and less heat is taken in.

34. Reversible Reactions and Closed Systems Temperature and equilibria A + B C + D If the forward reaction (i.e. going from left to right) is EXOTHERMIC and heat energy is given out……..

35. Reversible Reactions and Closed Systems Temperature and equilibria A + B C + D If the forward reaction (i.e. going from left to right) is EXOTHERMIC and heat energy is given out…….. Then if the temperature is increased.

36. Reversible Reactions and Closed Systems Temperature and equilibria A + B C + D If the forward reaction (i.e. going from left to right) is EXOTHERMIC and heat energy is given out…….. Then if the temperature is increased. The yield of products is decreased, and less heat is given out.

37. Reversible Reactions and Closed Systems Temperature and equilibria A + B C + D If the forward reaction (i.e. going from left to right) is EXOTHERMIC and heat energy is given out…….. Then if the temperature is decreased.

38. Reversible Reactions and Closed Systems Temperature and equilibria A + B C + D If the forward reaction (i.e. going from left to right) is EXOTHERMIC and heat energy is given out…….. Then if the temperature is decreased. The yield of products is increased, and more heat is given out.

39. Reversible Reactions and Closed Systems What about gases and equilibria ?

40. Reversible Reactions and Closed Systems Pressure and equilibria

41. Reversible Reactions and Closed Systems Pressure and equilibria

42. Reversible Reactions and Closed Systems Pressure and equilibria

43. Reversible Reactions and Closed Systems Pressure and equilibria Increasing the pressure will push the reaction in the direction of fewer molecules

44. Reversible Reactions and Closed Systems Pressure and equilibria Increasing the pressure will push the reaction in the direction of fewer molecules Increased pressure

45. Reversible Reactions and Closed Systems Pressure and equilibria Increasing the pressure will push the reaction in the direction of fewer molecules Decreased pressure

46. End of Equilibria In this lesson I have covered: Reversible reactions Reversible reactions in closed systems

47. THANKS FOR YOUR KIND ATTENTION MD KAMRUL ALAM KHAN M Phil on Electrochemistry (ongoing), Department of Chemistry, SUST . B.Sc Honors in Chemistry ( SUST), M.Sc in Chemistry ( SUST), CCNA (All through First class) Chemistry Teacher, British Bangladesh International School & College, Ex- Assistant Teacher of Chemistry, The Sylhet Khajanchibari International School & College, Ex-Lecturer of Chemistry, Metrocity Womens College, Ex- Lecturer of Chemistry, Sylhet Cadet Madrasah , Ex- Senior Quality Control Officer, Silco Pharmaceuticals Limited. Ex- Territory Officer ( Feni ), Akij Corporation Limited Cell: 01719014276, 01557704046 Email: [email protected]